1. Field of the Invention
The field of this invention is analyte detection, particularly labels employed in analyte detection.
2. Background of the Invention
Analyte detection, in which a sample is assayed for the presence of a particular analyte of interest, is critical to a variety of fields. For example, analyte detection protocols are employed in the characterization of complex mixtures, the identification and characterization of novel compounds of interest, and the like, both in industry and academia. Analyte detection also plays a role in medicine, particularly in the diagnosis of disease. In such applications, a sample from a patient is assayed for the presence of one or more specific analytes indicative of the disease being diagnosed. Environmental monitoring applications, such as the monitoring of pollutants and toxins, also employs analyte detection protocols.
Where an analyte of interest is not readily measured directly, the use of a detectable label is required. A variety of detectable labels have been developed over the years for use in analyte detection. These include both directly and indirectly detectable labels. Directly detectable labels include radioisotopes, enzymes, fluorescent and chemiluminescent agents, or other labels capable of being directly detected. Where an indirectly detectable label is employed, it is generally a member of a signal producing system such as a second stage antibody or reagent that is used to amplify the signal. Such reagents are well known in the art. For example, the primary antibody may be conjugated to biotin, with horseradish peroxidase-conjugated avidin added as a second stage reagent. Alternatively, the secondary antibody may be conjugated to a fluorescent compound, e.g. fluorescein, rhodamine, Texas red, etc. Final detection uses a substrate that undergoes a color change in the presence of the peroxidase.
Despite the wide variety of different labeling agents that have been developed over the years for use in analyte detection, there is still an interest in developing new ones. Of particular interest would be the development of sensitive labels that can simultaneously detect small quantities of analytes present in complex mixtures by methods that do not require preparation steps prior to detection.
U.S. Patents of interest include: U.S. Pat. Nos. 5,573,905 and 5,723,598. Also of interest are Akeson et al., xe2x80x9cMicrosecond time-scale discrimination between polycytidylic acid, polyadenylic acid and polyuridylic acid as homopolymers or as segments within single acid as homopolymers or as segments within RNA moleculesxe2x80x9d Biophys. J (1999) 77:3227-3233; Wonderlin et al., xe2x80x9cOptimizing planar lipid bilayer single-channel recordings for high resolution with rapid voltage stepsxe2x80x9d Biophys. J. (1990) 58:289-297; and Kasianowicz, et al., xe2x80x9cCharacterization of individual polynucleotide molecules using a membrane channel,xe2x80x9d Proc. Natl. Acad. Sci. USA (1996) 93: 13770-13773. See also, Benoit et al., J. Am. Chem. Soc. (1999) 121:3904; Hawker et al., Paper 136, PMSE Division, 217th ACS Meeting, Anaheim (1999); Hawker et al., Acc. Chem. Res. (1997) 30:373; Dao et al., J. Polymer Science Part A-Polymer Chemistry (1998) 36:2161-2167; Keck et al., J. Org. Chem. (1996) 61:359.
Targeted molecular bar codes and methods for their use in analyte detection are provided. The subject targeted molecular bar codes comprise a molecular bar code bonded to a member of a specific binding pair, usually through a linking group. The molecular bar codes are charged polymeric compounds, preferably negatively charged compounds, e.g. negatively charged block copolymers, that can be detected by a nanopore. The subject targeted molecular bar codes find use in a variety of different analyte detection applications, including screening and diagnostic applications.